Flange seal

ABSTRACT

A flange seal for use in sealing flanges between internalcombustion engine parts and the like comprises a sheath member having a channel shaped cross section including two planar arms, a generally U-shaped intermediate portion connecting the arms, resilient supporting means located between the arms, the arms of the sheath, but not the connecting portion being engaged with the flanges of the joint to be sealed.

United States Patent Friedhelm Stecher Burscheid, Germany 777,068

Nov. 19, 1968 Mar.30, 1971 Goetzewerke Burscheid, Germany Nov. 21, 1967Germany Inventor Appl, No. Filed Patented Assignee Priority FLANGE SEAL11 Claims, 6 Drawing Figs.

U.S. CI 277/ 153, 277/231 Int. Cl F02f 5/00,

F02f 1 H00 Field of Search Primary Examiner-Robert M. WalkerAttorney-Spencer and Kaye ABSTRACT: A flange seal for use in sealingflanges between intemaI-combustion engine parts and the like comprises asheath member having a channel shaped cross section including two planararms, a generally U-shaped intermediate portion connecting the arms,resilient supporting means located between the arms, the arms of thesheath, but not the connecting portion being engaged with the flanges ofthe joint to be sealed.

' PATENTED mm 'FIG.2

Attorneys FLANGE SEAL BACKGROUND OF THE INVENTION The present inventionrelates to seals for flanges and more particularly to a device forsealing the region between planar surfaces of separate parts in internalcombustion engines and the like. In the prior art the sealing edge ofgaskets used adjacent to combustion chambers have been metallicallyreinforced. The metallic border of the sealing edges protects softmaterial, e.g. asbestos webbing, from the hot combustion gases and fromthe high pressures occurring in the combustion chamber and, alsoprovides a more effective seal by increasing sealing pressure in thearea of the reinforcement. The edge reinforcement of the sealing plateoften comprises a metal strip which is bent into a U- or C-shape to formtwo arms which enclose the sealing edge.

In this type of seal, supporting or suspension elements have additionalto the gasket itself, sometimes been provided between the two mm of thesheath element in order to increase the elasticity of the sealing ring.Such suspension elements have also been provided for sealing ringscomprising U- or C-shaped sheath members used without gaskets in sealingpipelines and the like as well as combustion chambers.

During installation, the .sealing thickness is reduced because thesealing gap, i.e., the distance between the two arms of the sleevedecreases as the'clamping screws or their equivalent are tightened.Thus, in use the curvature of the portion of the sheath element betweenthe two arms increases. If vibration occurs during operation between thetwo flanges which the arms contact, bending stresses are created on thecurved connecting portion. Such vibrations occur, for example, duringthe operation of intemal-combustion engines as a result of variations inpressure in the area to be sealed and because of imbalances in theengine. These stresses often lead to premature fatigue breaks in thecurved region of the sleeve.

In one known type of seal the free arm ends of the sheath element aresupported within recesses in the soft material of the gasket. Theremaining portions of the arms and the curved portion abut against thesealing surfaces under the pressure created by the deformation of thesleeve element. Because the arm ends are mounted in recesses,undesirable warping of the cylinder walls of. the internal-combustionengines is avoided and the curved region of the sleeve is less heavilystressed during installation. However, the continuous contact of botharms with adjacent engine parts causes transfer of vibrations to thesheath element and its durability is reduced, particularly in the curvedregion.

The uses of other material for the sleeve element or differentthicknesses of material is not feasible for economic and particularlyspatial reasons. The sealing thickness in the clamped state is oftenonly I to 2 mm. Thus, a way must be found to substantially removevibrations from portions of the sheath element which are likely tobreak.

SUMMARY OF THE INVENTION Among the objects of the present invention isthe elimination of the tendency of the sleeve element to break due tofatigue stresses.

A further object of the invention is the reduction of the transmissionof vibrations to the points of the sheath elements that are likely tobreak during use.

These and other objects of the invention are accomplished by shaping thecross section of the sheath element in such a way that the insertedsupporting element within the sheath acts only on the free arm ends.Only the supported arm ends of the sheath are in sealing contact withadjacent surfaces of the engine parts. The remaining unsupported armregions and the curved portion of the sheath element extend freely intothe sealing gap even subsequent to the plastic deformation which occursafter tightening of the seal. This connecting portion does notcontinuously contact adjacent vibrating engine surfaces under pressure.Transfer of vibrations from the flanges M 0- -i nrl rnninn is thuimnnssihln Direct vibration transfer occurs only to the free arm endswhich are pressed against vibrating engine surfaces where they form acontinuous seal by the resilience of the supporting clement disposedbetween them. There is an indirect transfer of vibrations over theadjacent arm region into the curved region of the sheath element.However, since the vibration width of the sealing gap and its influenceon the curved region of the sleeve element is dependent on theunsupported length of the arm disposed therebetween, the vibrationalinfluence can be sufficiently reduced, if the length of the arms isappropriate, so that the sleeve element will no longer break in the areaof its sharpest curvature.

According to one embodiment of the invention the sheath element isprovided with a generally U-shaped cross section in which the spacing ofthe legs of the U decreases from the free arm ends to the area ofsharpest curvature. The resulting sharp curvature of the sheath elementhas little adverse effect since the element is made of relatively softmaterial, for example a copper or aluminum alloy, and the deformation ispurely plastic and no further deformation occurs during the lateroperational state.

According to another embodiment of the invention the cross-sectionalwidth of the sheath element is reduced in steps, the steps beingprovided in one or both sheath element arms. If the reduction in sizeoccurs in one side only the other arm of the sheath element contacts theadjacent surface over its entire length. Vibrations are transferred tothe entire sheath element, but they do, not lead to a permanent changein curvature of the element and thus do not place additional stresses onthe same.

According to another embodiment of the invention the cross section ofthe sheath element remains unchanged but the diameter of the annularsealing edge of the gasket used with it is appropriately reduced so thatin the installed state the por tion of the sheath element which is notin contact with the supporting element and the adjacent engine partsfreely extends into the chamber to be sealed.

According to another embodiment of the invention a constriction isplaced in the arms of the sheath element in the form of crimps or thelike so as to hold the supporting or suspension element in place, and tocenter the sheath element in use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view of the headand block of an internal-combustion engine having a gasket and anassociated sheath element installed therein.

FIG. 2 is a sectional view similar to FIG. I of a gasket and anassociated sheath element in which all curvature of the sheath elementoccurs on one side.

FIG. 3 is a sectional view similar to FIG. 2 of still another embodimentof the invention in which a metallic coil spring is inserted between thearms of the sheath element to provide additional biasing effect.

FIG. 4 is a sectional view similar to FIG. 2 in which the connectingportion of the sheath member between the arms decreases in size insteps.

FIG. 5 is a sectional view similar to FIG. 2 in which the sheath elementis formed of separate metallic plates joined by welding.

FIG. 6 is a sectional view similar to FIG. 2 in which a constriction isprovided in the arms in order to hold the support ing element in place.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. I shows a gasket 4 of softmaterial installed between the cylinder head I and the cylinder block 2.The edge 5 of this gasket facing the combustion chamber 3 ismetallically armored in order to shield the soft material, e.g.,asbestos webbing, from the hot combustion gases and from the highpressures. The metallic armor consists of a metal strip having aV-shaoed cross section whose two arms 7, 8, which are parallel to eachother, enclose the edge of the soft gasket 4 and form a seal at theflange surfaces 9, of the cylinder block 2 or of the cylinder head 1,respectively. The end 5 of the soft gasket which extends between thearms 7, 8 here acts as a resilient supporting member. Between the twoarms 7, 8 and the curved region II of the sleeve 6 a further unsupportedsheath portion 12 extends which does not abut against the flangesurfaces 9, 10. During vibrations of the sealing gap, i.e., during acontinuously changing distance between the two arms 7, 8 the vibrationsat the endangered sleeve portions are reduced by the lever action of thefree length of the arms and thus do not lead to premature fatiguebreaks.

In the embodiment according to FIG. 2 the cross section of the sleeve isso constructed that only one arm 13 with its unsupported portion 14 islifted off a countersealing surface 15 whereas the other am 16 restsagainst the sealing surface 17 over its entire length.

FIG. 3 shows a cross section through a sealing edge similar to FIG. 1.The only difference is that a coil spring element 17 is here providedbetween the two arms 20, 21 which are in sealing contact with the flangesurfaces l8, 19.

The flange seal according to FIG. 4 comprises only a sheath 22 having anapproximately U-shaped cross section which decreases in steps on the oneside, a spring element in the form of an annular coil spring 25 beinginserted between the two sealing arm ends 23, 24. No internal gasket ofsoft material is provided, but it may be, as well as in the embodimentsshown in FIGS. 5 and 6.

In the embodiment shown in FIG. 5 the sheath partially enclosing theresilient element 26 comprises two metal strips 27, 28 having anapproximately S-shaped profile. lts contacting arm ends 29, 30 aretightly connected with each other over the entire periphery, forexample, by welding. This embodiment has the advantage that the sleeveis not disproportionately stressed by too sharp a curvature at anypoint.

The sealing ring 31 shown in FIG. 6 has a much smaller diameter thanthose described above so that the sleeve portion 34 which does not restagainst the flange surfaces 32. 33 freely extends into the combustionchamber 35 to be sealed. The inserted spring element 40 is centered bytwo crimps 38, 39 provided in the arms 36, 37 of the sleeve. Since thesleeve portion 34 freely extends into the combustion chamber itscurvature may be equal to or greater than the size of the sealing gap.

It will be apparent that there has been provided a flange seal in whichtransmission of vibrations to the connecting portion joining the flangesis substantially reduced, and in which the possibility of failurethrough fatigue is less likely.

It will be understood that the above description of the presentinvention is susceptible to various modifications changes andadaptations.

lclaim:

1. In a flange seal subjectable to hot combustion gases and highpressures for sealing the joint between planar flange surfaces ofadjacent parts ofintemal-combustion engines and the like of the typecomprising a metallic channel-shaped sheath element having in crosssection at its free ends a pair of planar arms and a resilientsupporting element disposed between the planar arms the improvement inwhich only the planar arms of the sheath element are in contact with theadjacent flange sur faces. in which the portion of the sheath elementconnecting said arms is out of contact with the adjacent flanges in theoperative position, and in which the resilient supporting element ispresent between the planar arms up to, and not beyond, the point atwhich the contact between the sheath element and the flange surfaces islost with the beginning of the connecting portion.

2. The structure of claim I in which the intermediate connecting portionof the sheath is generally U-shaped in cross section and in which thespacing of the legs of the U decreases from the region of the planararms to a curved area joining the legs of the U.

3. The structure of claim 2 in which the said U-shaped cross sectiontapers uniformly from said planar arms to the said curved area.

4. The structure of claim 2 in which the legs of the said U 1 decreasesin spacing in steps between the said planar arms and the said curvedarea.

5. The structure of claim 2 in which one leg of the said U- shapedconnecting portion is substantially planar with the adjacent planar armand the other leg extends to the other planar arm.

6. The structure of claim 1 in which the intermediate connecting areaextends into a chamber to be sealed.

7. The structure of claim 1 in which a constriction is formed in thesheath element adjacent each of the planar arms and extends toward theopposite planar arm and in which the resilient means have greatercross-sectional dimensions than the distance between the constrictionsin the engaged position of the seal and are positioned in engagementwith the planar arms and the constrictions but not said connectingportion whereby the resilient supporting element is held in position bythe constrictions.

8. The structure of claim 1 in which the resilient means is a sealinggasket.

9. The structure of claim I in which the resilient means is a springelement.

10. The structure of claim 1 in which the resilient means is a coilspring arranged with its axis substantially parallel to the plane of thearms of the sheath element.

11. The structure of claim I in which the sheath element comprisesseparate plates, each having an arm portion and a connecting portion,and means joining the edges of the connecting portion of each plate.

1. In a flange seal subjectable to hot combustion gases and highpressures for sealing the joint between planar flange surfaces ofadjacent parts of internal-combustion engines and the like of the tYpecomprising a metallic channel-shaped sheath element having in crosssection at its free ends a pair of planar arms and a resilientsupporting element disposed between the planar arms the improvement inwhich only the planar arms of the sheath element are in contact with theadjacent flange surfaces, in which the portion of the sheath elementconnecting said arms is out of contact with the adjacent flanges in theoperative position, and in which the resilient supporting element ispresent between the planar arms up to, and not beyond, the point atwhich the contact between the sheath element and the flange surfaces islost with the beginning of the connecting portion.
 2. The structure ofclaim 1 in which the intermediate connecting portion of the sheath isgenerally U-shaped in cross section and in which the spacing of the legsof the U decreases from the region of the planar arms to a curved areajoining the legs of the U.
 3. The structure of claim 2 in which the saidU-shaped cross section tapers uniformly from said planar arms to thesaid curved area.
 4. The structure of claim 2 in which the legs of thesaid U decreases in spacing in steps between the said planar arms andthe said curved area.
 5. The structure of claim 2 in which one leg ofthe said U-shaped connecting portion is substantially planar with theadjacent planar arm and the other leg extends to the other planar arm.6. The structure of claim 1 in which the intermediate connecting areaextends into a chamber to be sealed.
 7. The structure of claim 1 inwhich a constriction is formed in the sheath element adjacent each ofthe planar arms and extends toward the opposite planar arm and in whichthe resilient means have greater cross-sectional dimensions than thedistance between the constrictions in the engaged position of the sealand are positioned in engagement with the planar arms and theconstrictions but not said connecting portion whereby the resilientsupporting element is held in position by the constrictions.
 8. Thestructure of claim 1 in which the resilient means is a sealing gasket.9. The structure of claim 1 in which the resilient means is a springelement.
 10. The structure of claim 1 in which the resilient means is acoil spring arranged with its axis substantially parallel to the planeof the arms of the sheath element.
 11. The structure of claim 1 in whichthe sheath element comprises separate plates, each having an arm portionand a connecting portion, and means joining the edges of the connectingportion of each plate.